Objective: Retinol-binding protein 4 (RBP4) is an adipokine responsible for vitamin A (retinol) transportation. Studies associated RBP4 increased levels with severity of type 2 diabetes mellitus (T2DM) and insulin resistance (IR). The study aimed to quantify RBP4 serum standards in women with a wide range of body mass index (BMI) and glucose tolerance level. Subjects and methods: Cross-sectional study was performed with 139 women divided into three groups: Group 1 (lean-control, n = 45) and Group 2 (obese, n = 53) with normal glucose tolerance and group 3 (obese with T2DM, n = 41), called G1, G2 and G3. Were assessed clinical, biochemical, anthropometric and body composition parameters. Results: According to data analysis, we obtained in G1 higher RBP4 levels (104.8 ± 76.8 ng/mL) when compared to G2 (87.9 ± 38 ng/mL) and G3 (72.2 ± 15.6 ng/mL) levels. Also, were found: in G1 positive correlations of RBP4 with BMI (r = 0.253), glycated hemoglobin (r = 0.378) and fasting insulin (r = 0.336); in G2 with glycated hemoglobin (r = 0.489); in G3 with glycated hemoglobin (r = 0.330), fasting glucose (r = 0.463), HOMA-IR (r = 0.481). Conclusions: Although RBP4 have shown lower levels in diabetic and obese, a strong correlation with HOMA-IR index highlights that, in our study, there is growing IR when there is an increasing in RBP4 levels.587709714Kahn, S.E., Prigeon, R.L., Schwartz, R.S., Fujimoto, W.Y., Knopp, R.H., Brunzell, J.D., Obesity, body fat distribution, insulin sensitivity and Islet beta-cell function as explanations for metabolic diversity (2001) J Nutr, 131 (2), pp. 354S-360SKahn, S.E., Hull, R.L., Utzschneider, K.M., Mechanisms linking obesity to insulin resistance and type 2 diabetes (2006) Nature, 444 (7121), pp. 840-846Kershaw, E.E., Flier, J.S., Adipose tissue as an endocrine organ (2004) J Clin Endocrinol Metab, 89 (6), pp. 2548-2556Després, J.P., Body fat distribution and risk of cardiovascular disease: An update (2012) Circulation, 126 (10), pp. 1301-1313Vague, J., Les Obésités: Etudes biométriques (1947) Press Medical, (30), p. 339Sjöström, C.D., Håkangård, A.C., Lissner, L., Sjöström, L., Body compartment and subcutaneous adipose tissue distribution--risk factor patterns in obese subjects (1995) Obes Res, 3 (1), pp. 9-22Ravussin, E., Smith, S.R., Increased fat intake, impaired fat oxidation, and failure of fat cell proliferation result in ectopic fat storage, insulin resistance, and type 2 diabetes mellitus (2002) Ann N Y Acad Sci, 967, pp. 363-378Trayhurn, P., Wood, I.S., Adipokines: Inflammation and the pleiotropic role of white adipose tissue (2004) Br J Nutr, 92 (3), pp. 347-355Berg, A.H., Scherer, P.E., Adipose tissue, inflammation, and cardiovascular disease (2005) Circ Res, 96 (9), pp. 939-949Fantuzzi, G., Cytokines: Pulling the body together as a whole (2011) ScientificWorldJournal, 11, pp. 2506-2508Colantuoni, V., Romano, V., Bensi, G., Santoro, C., Costanzo, F., Raugei, G., Cloning and sequencing of a full length cDNA coding for human retinol-binding protein (1983) Nucleic Acids Res, 11 (22), pp. 7769-7776Oh, K.J., Park, J., Kim, S.S., Oh, H., Choi, C.S., Koo, S.H., TCF7L2 modulates glucose homeostasis by regulating CREB-and FoxO1--dependent transcriptional pathway in the liver (2012) PLoS Genet, 8 (9), p. 1002986Gnudi, L., Shepherd, P.R., Kahn, B.B., Over-expression of GLUT4 selectively in adipose tissue in transgenic mice: implications for nutrient partitioning (1996) Proc Nutr Soc, 55 (1B), pp. 191-199Villarroya, F., Iglesias, R., Giralt, M., Retinoids and retinoid receptors in the control of energy balance: novel pharmacological strategies in obesity and diabetes (2004) Curr Med Chem, 11, pp. 795-805Ziouzenkova, O., Orasanu, G., Sharlach, M., Akiyama, T.E., Berger, J.P., Viereck, J., Retinaldehyde represses adipogenesis and diet--induced obesity (2007) Nat Med, 13 (6), pp. 695-702Yang, Q., Graham, T.E., Mody, N., Preitner, F., Peroni, O.D., Zabolotny, J.M., Serum retinol binding protein 4 contributes to insulin resistance in obesity and type 2 diabetes (2005) Nature, 436 (7049), pp. 356-362Basualdo, C.G., Wein, E.E., Basu, T.K., Vitamin, A., (retinol) status of first nation adults with non-insulin-dependent diabetes mellitus (1997) J Am Coll Nutr, 16 (1), pp. 39-45Abahusain, M.A., Wright, J., Dickerson, J.W., De Vol, E.B., Retinol, alpha-tocopherol and carotenoids in diabetes (1999) Eur J Clin Nutr, 53 (8), pp. 630-635Klöting, N., Fasshauer, M., Dietrich, A., Kovacs, P., Schön, M.R., Kern, M., Insulin-sensitive obesity (2010) Am J Physiol Endocrinol Metab, 299 (3), pp. 506-515Graham, T.E., Yang, Q., Blüher, M., Hammarstedt, A., Ciaraldi, T.P., Henry, R.R., Retinol-binding protein 4 and insulin resistance in lean, obese, and diabetic subjects (2006) N Engl J Med, 354 (24), pp. 2552-2563Kotnik, P., Fischer-Posovszky, P., Wabitsch, M., RBP4: A controversial adipokine (2011) Eur J Endocrinol, 165 (5), pp. 703-711Munkhtulga, L., Nagashima, S., Nakayama, K., Utsumi, N., Yanagisawa, Y., Gotoh, T., Regulatory SNP in the RBP4 gene modified the expression in adipocytes and associated with BMI (2010) Obesity (Silver Spring), 18 (5), pp. 1006-1014Kovacs, P., Geyer, M., Berndt, J., Klöting, N., Graham, T.E., Böttcher, Y., Effects of genetic variation in the human retinol binding protein-4 gene (RBP4) on insulin resistance and fat depot-specific mRNA expression (2007) Diabetes, 56 (12), pp. 3095-3100Munkhtulga, L., Nakayama, K., Utsumi, N., Yanagisawa, Y., Gotoh, T., Omi, T., Identification of a regulatory SNP in the retinol binding protein 4 gene associated with type 2 diabetes in Mongolia (2007) Hum Genet, 120 (6), pp. 879-888Craig, R.L., Chu, W.S., Elbein, S.C., Retinol binding protein 4 as a candidate gene for type 2 diabetes and prediabetic intermediate traits (2007) Mol Genet Metab, 90 (3), pp. 338-344Santoro, N., Perrone, L., Cirillo, G., Brienza, C., Grandone, A., Cresta, N., Variations of retinol binding protein 4 levels are not associated with changes in insulin resistance during puberty (2009) J Endocrinol Invest, 32 (5), pp. 411-414Ulgen, F., Herder, C., Kühn, M.C., Willenberg, H.S., Schott, M., Scherbaum, W.A., Association of serum levels of retinol-binding protein 4 with male sex but not with insulin resistance in obese patients (2010) Arch Physiol Biochem, 116 (2), pp. 57-62Henze, A., Frey, S.K., Raila, J., Tepel, M., Scholze, A., Pfeiffer, A.F., Evidence that kidney function but not type 2 diabetes determines retinol-binding protein 4 serum levels (2008) Diabetes, 57 (12), pp. 3323-3326Lukaski, H.C., Bolonchuk, W.W., Hall, C.B., Siders, W.A., Validation of tetrapolar bioelectrical impedance method to assess human body composition (1986) J Appl Physiol (1985), 60 (4), pp. 1327-1332Matthews, D.R., Hosker, J.P., Rudenski, A.S., Naylor, B.A., Treacher, D.F., Turner, R.C., Homeostasis model assessment: Insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man (1985) Diabetologia, 28 (7), pp. 412-419Gregoire, F.M., Adipocyte differentiation: From fibroblast to endocrine cell (2001) Exp Biol Med (Maywood), 226 (11), pp. 997-1002